The present invention is directed to a feed circuit for feeding at least one user with a dc voltage acquired from an impressed direct current. The feed circuit has a controllable switch in a current branch which is connected in parallel to an input of the feed circuit and that is controllable with a pulse width modulator dependent on a voltage that is the determining factor for the output voltage.
U.S. Pat. No. 4,620,271 discloses such a feed circuit. In the prior art feed circuit, a voltage converter is arranged in iteration with a switching controller. A current sensor for the input current is provided at the input of the voltage converter. The voltage converter is driven with the current sensor and with a control circuit connected to the current sensor such that it outputs a reduced output voltage or, reduced output power for input currents above a predetermined limit value. As a result the feed circuit is largely insensitive to overload conditions. In particular, the prior art feed circuit can automatically return to normal operating condition following an overload condition.